The discovery of how bronze is made was probably accidental, but it to be an important event.
We ______ to clean the blackboard every day.
The old man is ______ under the tree and ______ a paper.
-Can you stand ______ in that way?- Absolutely not.
Don't forget ______ the light when you leave the office.
You'd better not ______ your coat, or you'll get cold.